Correlation Between Plasma Brain-Derived Neurotrophic Factor And Depressive Symptoms And Cognitive Function In Patients With First-Episode Major Depressive Disorder

Objective:Major depressive disorder(MDD),also known as depression,is a kind of psychiatric disorder with high morbidty and disability rate,and cognitive symptoms are gradually recognized as a core symptom of MDD,which has a significant impact on the prognosis and efficacy of patients.In recent years,there is a view that brainderived neurotrophic factor(BDNF)is closely related to antidepressant efficacy and cognitive function by participating in the pathophysiological process of depression.However,most studies were limited to cross-sectional studies.This study investigated the changes of plasma BDNF in first-episode MDD patients before and after antidepressant treatment,aiming to determine the relationship between plasma BDNF level and antidepressant efficacy and cognitive function.Methods:Sixty patients with first-episode MDD,aged 18-45 years,were enrolled and treated with escitalopram or venlafaxine for 4 ’weeks.Blood samples were collected at baseline and 4 weeks after treatment,respectively,and plasma BDNF levels were determined by ELISA.The severity of depressive symptoms before and after treatment was assessed by 17 item Hamilton Depression Scale(HAMD-17).Cognitive function was assessed by the MATRICS Consensus Cognitive Battery(MCCB).Fifty healthy controls(HCs)were also enrolled to assess cognitive function using MCCB,and blood samples were collected to detect BDNF levels in plasma.The t test was used to compare the cognitive performance of the two groups,and covariance analysis was used to compare the BDNF level between MDD and HCs.Pearson’s correlation analysis displayed the relationship between plasma BDNF level and depressive symptoms and cognitive function.In further analyze,linear regression model was used to explore the correlation between BDNF level and depressive symptoms and cognitive function changes.Results:The plasma BDNF level in MDD group was significantly decreased compared with HCs group(P<0.05).MDD patients showed remarkable cognitive damnnification in three modules including speed of processing(SOP),verbal learning(VBL)and visual learning(VSL)which scores were all lower than those of HCs(P<0.05).After 4 weeks of antidepressant treatment,BDNF level was higher than at baseline,but the difference was not statistically significant(P>0.05).Pearson’s correlation analysis showed that there was no correlation between BDNF level and depressive symptoms and cognitive function.Baseline BDNF level did not predict changes in depressive symptoms and cognitive function.Conclusions:The plasma level of BDNF in patients with first-episode MDD was significantly lower than that in healthy people,accompanied by significant cognitive impairment.Cognitive function improved after short-term antidepressant treatment,but BDNF levels did not increase significantly.However,there was no correlation between BDNF level and the change of depressive symptoms and cognitive function before and after treatment,which could not be used as a biological indicator to predict the change of depressive symptoms and cognitive function in first-episode MDD patients.